Do worms cause diarrhoea in dogs?

Answer 1

It is possible for intestinal worms to cause diarrhea in dogs, although this is not as common as one might think. Typically, dogs are the definitive host for their common intestinal worms, so there may be very few clinical signs of the infestation unless it is severe. More commonly you may see eggs passed in the feces, itchiness or irritation of the tailhead and peri-anal area and slowly degrading body condition even as the abdomen stays the same size or increases.

Diarrhea can also be caused by bacterial or viral infections of the intestinal tract, an improper diet (such as suddenly being fed turkey gravy when staying with a pet sitter for a few days), stress (anecdotally, the dogs of veterinary students tend to break with unexplained diarrhea around the same time as midterm and final exams) or other inflammatory conditions of the bowels.

If the diarrhea does not resolve within about 48 hours, I would suggest scheduling a visit with a veterinarian within the next day or so. Your veterinarian would appreciate a fresh stool sample if you can bring that in as well.